Abstract
p-Chlorophenyl N-(p-methoxyphenyl) chlorophosphoramidate was used to phosphorylate the 3'-hydroxyl groups of N, 5'-O-protected deoxyribonucleosides. These nucleotides served as the 3'-terminal unit in the synthesis of fully protected oligonucleotides, and the p-anisidine was readily removed by treatment with isoamyl nitrite to generate the 3'-phosphodiester for condensations. This approach was suitable for complete purification of fully protected oligonucleotides by chromatography, which was essential to obtain products. Deoxyoligonucleotides complementary to the anticodon loop of E. coli tRNAMetf were synthesized by condensation of di-, tri- and tetranucleotide blocks (dATp, dTATp and dTTATp) with protected dGAG. The products (dA-T-G-A-G, d-T-A-T-G-A-G and d-T-T-A-T-G-A-G) were isolated by anion-exchange or reverse phase high pressure liquid chromatography.
